The present invention relates to a binding device for filing, and in particular to a binding device used as, for example, a plastic ring type notebook or a file, a binder, or the like for binding a leaf with binding holes.
Conventionally, a notebook that binds a leaf with holes by using a ring-shaped member can, along its ring shape, spread the leaf through 360 degrees, in other words, not only open the leaf but also flip over the leaf to lay its front side and its reverse side on each other, thus utilizing half a space utilized by a notebook openable through only 180 degrees. However, the plastic ring type notebook has a disadvantage that it does not permit leaf replacement.
On the other hand, a notebook with binding devices of Japanese Patent No. 3440356 and Japanese Utility Model Application Laid-Open Publication No. H7-17578, in other words, a notebook with openable/closable binding rod portions that bind a leaf permits leaf replacement.    Patent Document 1: Japanese Patent No. 3440356    Patent Document 2: Japanese Utility Model Application Laid-Open Publication No. H7-17578
However, the binding device of Japanese Patent No. 3440356 is a binding device composed of two main members (1) having a plurality of comb portions (2), wherein a slidable ring member (4) is provided at an end of the main member (1a) and inside of this ring member (4) has almost the same shape as or a slightly smaller shape than an outer shape obtained by integrating the main member (1a) and the main member (1b). For the leaf replacement, this binding device, upon fitting of fitting means provided at tips of the plurality of the comb portions after separating the two main members from each other, requires relatively many man-hours for fitting the many comb portions.
Moreover, the binding device of Japanese Utility Model Application Laid-Open Publication No. H7-17578 has a first member and a second member with a plurality of uprising binding loops, pivotably fitted together by a common axis line. Therefore, although the first member and the second member do not separate from each other, a bar-type coupling portion for coupling the plurality of binding loops is formed at base portions of the binding loops 15 and 17, and a protruding portion 23 is provided in such a manner as to project from an inner side surface of this coupling portion. Accordingly, for example, even upon attempt to place the binding device on a desk to open it, outsides of the base portions of the binding loops hit a desk surface and thus the binding loops are not fully opened, thus making it relatively difficult to take-in and take-out the leaf. Additionally, integral molding with synthetic resin is difficult since it results in a complicated structure of a manufacturing die.
Therefore, it is a main object of the present invention to provide a binding device easily manufactured and having binding rods easily opened and closed for easy leaf replacement.